Sheriff’s deputies' use of force on inmates in Los Angeles County lockups has increased sharply in the first half of 2013, according to two reports presented to the county Board of Supervisors on Tuesday about ongoing efforts to reduce jail violence.

A report from special counsel Merrick Bobb found that the number of incidents rose nearly 29% from Jan. 1 to July 6 compared with the same period in 2012.

An official with the county Sheriff’s Department said there had been a 34% increase to date.

Terri McDonald, assistant sheriff for the custody division, said there had been 322 incidents this year, with the vast majority being low-level uses of force that do not cause injury or prompt the filing of a grievance by the inmate. Seven of the cases involved the highest-level of force, resulting in major injury or appearing to be a clear violation of departmental policy, she said.

Both McDonald and Bobb said the increase probably reflected the improved reporting of when force is used on any of the 19,000 inmates housed in the nation’s largest jail system.

“I’m not too concerned at this point because you would expect force numbers to go up when you start requiring every use of force” to be tracked, McDonald said.

Improved reporting is part of a multi-pronged effort to reduce violence in the county’s jails, which is being investigated by the federal government.